Field of the Invention
The present invention relates to a contact unit and an inspection jig such as a probe card which are used for inspecting electrical performance of a semiconductor integrated circuit, for example.
Description of the Related Art
In general, an inspection jig such as a probe card which is used for inspecting electrical performance of a semiconductor integrated circuit includes a flexible substrate having contact portions in contact with electrodes of an object to be inspected (e.g. wafer). The flexible substrate has a block for pressing the flexible substrate against the object to be inspected on a back side which is an opposite side from a side where the contact portions are provided. The block is urged by an urging means such as a spring toward the object to be inspected, to impart a contact force with the object to be inspected to the flexible substrate.
On the occasion of inspecting the electrical performance, electrical signals at high frequency are transmitted between the inspection jig and an inspection apparatus (a tester) by way of a coaxial cable. The inspection jig is provided with a coaxial connector for detachably connecting the coaxial cable which is extended from the tester. The coaxial connector is electrically connected to the flexible substrate by soldering or the like. An electrical connection between the contact portion of the flexible substrate and the coaxial connector is achieved by a conductive pattern provided on the flexible substrate.
Patent Literature 1    Japanese Unexamined Patent Application Publication No. 2006-177971
The conductive pattern drawn from the contact portion on the flexible substrate has an inductance. Recently, it has become a problem that an influence of noise arising from the inductance of the conductive pattern since the increased speed (heightened frequency) of signals handled in measurements of the inspection jig has been progressing. A possible measure to reduce noise is to dispose a bypass capacitor. Though the bypass capacitor has a higher noise removal effect according as it comes closer to the contact portion, it is necessary for the bypass capacitor to be disposed apart more than a certain distance from the contact portion in order to avoid interference with the object to be inspected during the measurements. In the case of high-speed signals of several GHz, if the bypass capacitor is apart from the contact portion, it is difficult to make accurate measurements under the influence of noise on the conductive pattern between the bypass capacitor and the contact portion.